Emotion

Abstract

Emotions have impacts on a variety of behaviors in animals and human. But they are not easy to define, and there exist multiple definitions of emotions. In this chapter, the basic concepts, functions, and features of emotions are summarized, and the roles and natures of emotional facial expressions are introduced. Two main roles of emotion are distinguished: intra-individual (intra-personal) roles and inter-individual (inter-personal or social) roles. Emotion is related to primary drives that arise from innate needs, and hence have intra-individual roles. In addition, an emotional output of a person may influence the other’s emotion and behavior, and hence emotion has inter-individual roles.